<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8" />
		<title></title>
	</head>
	<body>
		<button id="btn">按钮</button>
		<button id="btn2">按钮</button>
		<script type="text/javascript">
			var oBtn = document.getElementById("btn")
			oBtn.onclick = function  () {
				alert("aa")
			}
			var oBtn2 = document.getElementById("btn2")
			
		</script>
	</body>
</html>
